Telephone-exchange system



June 10 1924.

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L. POLINKQWSKY TELEPHONE EXCHANGE SYSTEM June 10 1924. 1,497,284

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Patented June 10, 1924.

- ESTATES Lira roLinnowsxr, or anrwnnr BELGIUM, Assrenon To wears-Rnnncrnrc COMPANY, iNoonronAr-np, or new YORK, N. Y., A CORPORATION on NEWYORK.

TELEPHONE-EXCHANGE SYSTEM.

Application filed December 31, 1919. Serial No. 348,566.

To all whom it may concern:

Be it known that I, LIPA POLINKOWSKY, a citizen of Russia, residing at18 Rue .du Bastion, in Antwerp, --Belgium, have in vented certain newand useful Improvements in Telephone-Exchange Systems, of whiclrthefollowing is a full, clear, concise, and exact description.-

This invention relates to telephone exchange systems, and .moreparticularly to systems of the type in which automatic switchingapparatus is employed for setting up connections.

In automatic telephone systems in which selective switches, operated inaccordance with the revertive impulsecontrol principle, are used it iscustomary to provide register sending devices for the-purpose ofcontrolling these switches. The required designations maybe recorded onthe register senders in any suitable manner, as bygmeans'of an operatorskeyboard, impulse senders at the operators position .or impulse senderslocated at the subscribers substations. After the designation isrecorded, the register sender becomes eilective to selectively controlthe several selective switches to establish the desired connection.

The object of this invention is the :provision, in a system of thischaracter, of means whereby a selective switch .may be broughtunder thecontroloi anyone of a plurality of register senders :for the purpose ofoperatingthis switch to establish any one of a numberofdi-iierentclasses of connections.

A feature of theinvention relates to an arrangement inwhich connectionsare es tablisliedover a series of selective switches under the controlof a register sender,flone of such switches having associated therewitha second register sender, which is normally inoperative during the timesuch switchis being controlled by the first-sender. According to. thisfeature, when the ,selectire switch having the registersender RSSO?ciatedthercwith, is taken foruse in theestablishment of a differentclass of connection, suchsender is automatically placed in condition tocontrol the operation of said switch. d

Other features contemplated by this invention will'become apparent {fromthefollowing description and the appended claims.

distant exchange.

shown diagrammatically whereas the .cir-

Rei erring'to the drawings, Figs. 1, 2,3

and at, taken in order from left toright with .Fig. 5 beneath F ig. ft,illustrate a telephone ig. ,1 shows the calling end of a toll opcratorscordcircult in a first exchange and also the outgoing end of a pair oftrunks leading to a distant exchange. Fig. 2 shows system .in' whichthis invention is embodied.

the incoming ends of the trunks terminating in first group selectorswitches in the One 01": these switches is change. At the right of thevertical broken line in Fig. 3are shown the circuits and apparatus at atesting ope'rators position in the distant exchange. Fig. 4 shows gtW'Qfinal selector switches, one of which is illustrated diagrammaticallyand the other in detail. Fig. 5 illustrates a second register senderassociated with the circuits of the final selector switch shown in Fig..4.

In accordance with the arrangement shown in this system, the finalselector switch serves both asa toll operators final switch forestablishing connections to busy called lines, and also as atestingoperators switch for performing routine tests of the subscriberslines. *lVhen a call is extended to thewtoll operators position, shefirst inserts the plug of hercord circuit in a jack,

such as 2000f the trunk leading to .afirst group the called subscribersline belongs. The toll operator, by means of her impulse {sender2.12thereu ion sets uo a re ister sender such as the one shown at thebottom of Fig. 2, in accordance with the required number. The registersender having been positioned, then becomes operative to control theselectiveoperations of the firstgroup selector 210, second groupselector 215, and-the final selector 416, to. extend the connectionthrough to thecalled line 420. lithe called line 420 is found busy, asby being engaged in la local connection, overwhich toll calls should begiven preference, the toll operselector 210 in the exchange-to which atween the testing ator removes the plug of her cord circuit from jack200 and inserts it in the jack 202 of a special trunk circuit. She thensets up a connection over the special first group selector shown indetail in Fig. 2, second group selector 216 and the special finalselector switch shown in detail in Fig. 4. This final selector switch isarranged not to make a test of the subscribers line and can, therefore,complete a connection through to a called line regardless of whethersuch line is busy or idle. The toll operator then informs the calledsubscriber that a toll call is waiting and instructs him to release thelocal connection which, at the time, is holding his line engaged. Thetoll operator now removes the plug of her cord circuit from the jack 202of the special trunk and inserts it again in jack 200. The originalconnection is established once more through to the called line at whichtime the called subscriber will have released the local connectionpreparatory to receiving the incoming toll call. During theestablishment of connections of this character the final selector switchas well as the first and sec- 0nd and such additional group selectors asmay be required is controlled by the register sender associated with thecircuits of the first group selector switch.

hen the testing operator wishes to make a test of the subscribers lines,he appropriates the use of one of the special final switches for thispurpose. In this case the testing operator, by inserting plug 410 of hisconnecting circuit in either of the jacks 401 or 402, extends aconnection from his position to the special final selector switch Theextension of this connection places the register sender, shown in Fig.5,in' condition to be set up by impulses transmitted from the testingoperators position in accordance with the digits of the line that isdesired to be tested. The register sender having thus been positioned,is then operative to control the selective operation of the final switchto complete a connection beoperators position and the desiredsubscribers line.

A detailed description will now be given of the operation of the system.Assume first that a toll connection, incoming through the toll operatorsposition in the first exchange, is desired with the subscribers line 420in the second exchange. The toll operator in serts a plug 201 of hercord circuit in jack 200 of an idle trunk leading to the secondexchange. She then manipulates her impulse transmitter 212 to position aregister sender (not shown) in accordance with the number of the calledline. The register sender thereupon serves to control the operation ofthe first group selector 210, second group selector 215, and finalselector 416.. to complete the connection to the called subscribers line420. Assuming now that the called subscriber's line 420 is busy atthistime, this busy condition is indicated in any well-known manner tothe toll operator who thereupon removes the plug 201 from jack 200 andinserts it in jack 202 of the special trunk circuit 217, 218.

A circuit is then completed from battery through the winding of relay204, resist ance 205, sleeve of plug 201, sleeve of jack 202, left-handwinding of relay 235 to ground. Relay 204 attracts its armature andcloses a circuit for relay 206. Relay 206, being energized, connects thewindings of relay 207 and retardation coil 208 respectively, to the ringand tip sides of the toll operators cord circuit. Relay 235 attracts itsarmatures and closes a circuit from battery through the supervisorylamps 209, contact 224 (1 to 2) of sequence switch 220, front contactand left-hand armature of re lay 235, to ground at contact- 223, (1 to2). The lamps 209 indicate that the trunk circuit is busy. A circuit isalso completed from battery through the winding of relay 222, contactand right-hand armature of relay 235, contact 225 (1), conductor 217,

tip of jack 202, tip of plug 201, upper closed contacts of key 211,left-hand arma ture and contact of relay 206, retardation coil 208 toground. The relay 222 becomes energized and closes a circuit from groundover its armature and front contact, contact 226 (1), and winding ofsequence switch 220 to battery and ground. Sequence switch 220 moves outof position 1 and into position 3 whereupon the relay 222 isdeenergized. The supervisory lamps 209 are now illuminated in a circuitclosed to ground at the sequence switch contact 227 (2 to 18).

In position 3 of sequence switch 220 a sender selector 280 of thesequence switch type is started in operation to associate an idle senderwith the circuits of the first group selector switch. The circuit foroperating the sender selector 280 may be traced from battery through thewinding of said sender selector, contact 244 (3), back contact andarmature of relay 232 to ground at contact 282, closed in positions 1 to8.

It may be observed at this point that the sequence switch contactsincluded within the two horizontal broken lines in Fig. 2 are controlledby the sender selector 280. The sequence switch contacts above the upper broken line are controlled by sequence switch 220. The sequenceswitch contacts below the lower horizontal broken line are controlled bya sequence switch (not shown) of the register sender.

The sender selector sequence switch 280 commences to rotate and uponmoving to a position corresponding to an idle register sender, the relay234 is energized by means of a circuit from ground over the. contact282, right-hand high resistance winding of relay 234,. contact 228 (3),.conductor 293, contact 327, and thence by way of lead 328 to battery andground. The manner in which battery potential is applied to the lead 328at the: register. sender, is not shown in this.

disclosure; For a full and complete description of testing and: seizinga register sender of. the type illustrated in this disclosure, referenceis made to the British patent to lVestern Electric Company, Limited No.141,081, accepted April 15, 1920. It is suflicient to state herein thatan idle register sender will be identified by means of full batterypotential on the lead 328. Therefore, when the above traced circuit isclosed the relay 234 is energized and completes a circuit through itsleft-hand low resistance winding and the winding of reconductor 293'that other searching sender selectors will not be able to seize this regi'ster sender; Relay 232 becomes energized and opens the circuit of thesender selector switch 280, causing the latter to come to rest. Relay232 also closes a circuit from battery through the winding of sequenceswitch 220, contact 226 (3), front contactand armature of relay 232, toground at contact 282. Sequence switch 220 advances from position 3into. position 4. In position 4 of sequence switch 220, the followingcircuit is completed: battery, through the winding of relay 207, at thetoll operators position, contact and right-hand armature of relay 206,lower closed contacts of key 211, ring of plug 201, ring of jack 202,conductor 218, contact 229 (4), conductor 329, right-hand winding ofstepping relay 325, contact and left handarmatureof relay 339 to ground.Relay 207 attracts its armatureand opens the circuit of lamp 214. Thelamp 214, by ceasing to glow, indicates to the operator that an idleregister sender has been found and associated with the first groupselector.

The operator by depressing the listening key 203, closes a circuit frombattery through the left-hand winding of stepping relay 325, conductor330., contact 225 (4 conductor 217, tip of jack 202, tip of plug 201,upper closed contacts of key 211, upper contact of listening key 203,through the operators telephone set (not shown), the lower contact oflistening key 203, lower closed contacts of key 211, ring of plug20l,ring of jack 202, conductor 218, contact 229 (4), conductor 329,righthand winding of relay 325, contact and left-hand armature of relay339 to ground. When the register sender sequence switch (not shiown) haslates the sender 212 to position the registers of the register sender inaccordance with the designation of the called line. After the registershave been positioned, the fundamental circuit is closed for controllingthe brush-selecting operation of the first group selector as follows:battery, through the winding of relay 222, contact and right-handarmature of relay 235, contact 247 (4), 0011- ductor 296, contact 361,winding of stepping relay armature and contact of relay 357, to groundat contact 362. The relay 222 completes a circuit from ground over itsarmature and front contact,contact 226 (4), through the winding ofsequence switch 220 to battery and ground, for driving sequence switch220 into position 5. In position a circuit is completed from battery,through the winding of the trip spindle power magnet 248, contact 249(5), front contactand armature of relay 222 to ground. The power magnet248 causes the trip spindle 251 to be rotated to a position for trippingthe desired set of brushes. Each time the trip spindle 251 advances fromone trhqping position to another, a circuit is completed from battery,through the winding of relay 222. contact 237 (5) to ground at theinterrupter contact 250. 2 This circuit maintains the energization ofrelay 222 and causes the shunting of the stepping relay 355 in thefundamental circuit. In the manner described in the abovementionedBritish patent, the operation of the stepping relay 355 causes theregister to be returned to its normal position. The fundamental circuitis then opened atthe register sender and as soonas the tripping spindleis positionedin respect to the desired set of brushes, the interruptercontact 250 opens and causes the release ofthe relay 222. The relay 222by being deenergized, closes a circuit from ground over its armature andback Contact, contact 238 winding of sequence switch 220 to battery andground. Sequence switch 220 advances from position 5 over position6'into position 7. As soon as sequence switch 220 reaches position 6,

relay 222 is again energized in a circuit from battery, through thewinding of said relay, contact and right-hand armature of relay 235,contact 247 (6), conductor 293, contact and right-hand armature of relay339, to ground at the contact 445. Relay 222 therefore becomes energizedand opens the circuit closed over contact 238 when sequence switch 220reaches position 7, insuring that &

said sequence switch will not pass beyond position 7.

In position 7 the selected set of brushes are driven over the terminalsof thetrunk group to search for an idle trunk leading to a second groupselector. The brush car riage power magnet 241, which causes themovement of the selected set of brushes, is energized in a circuit frombattery through the winding of said magnet, contact 244 (7), backcontact and armature of relay 232, to ground at contact 282. Uponthe-test brush 252 making engagement with thetest terminal of an idletrunk, full battery potential will be found thereon and test relay 234is energized in a circuit closed at contact 228 (7), through theright-hand high resistance winding of said relay to ground at contact282. Relay 234 attracts its armature and completes a low resistance pathfrom test brush 252, contacts 228 (7) through the left-hand winding ofrelay 234, contact and armature ofthis relay and the winding of relay232 to ground. This low resistance circuit reduces the potential in thewell-known manner on the test terminal of the selected trunk to renderthe same busy to other switches. Relay 232 by being energized, opens thecircuit of the power magnet 241 and closes a circuit for the holdingiagne't 245 which serves to bring the brushes to rest accuratelycentered on the terminals of the selected trunk. The circuit of magnet245 may be traced from battery through the winding of magnet 2145,contact 240 (7), contact 226 (7), front contact and armature of relay232, to ground at contact 282. Relay 232 also closes a circuit frombattery through the winding of sequence switch 220, contact 226 (7),front contact and armature of relay 232 to ground at contact 282, movingsaid sequence switch from position 7, over position 8 and into position9.

The fundamental circuit is now closed at sequence switch contacts 255and 256 from the register sender through to the second group selectorshown diagrammatically at 216. In the well-known manner the brushselecting and trunk-hunting operations take place at the second groupselector to extend the connection over an idle trunk 413, 414, to afinal selector switch. When the test brush 230 of the second groupselector makes engagement with the test terminal 231 of trunk 413, 414,in the trunk-hunting operation, a circuit is closed from battery, throuh resistance 442 at the final selector switc contact 441 (1) of sequenceswitch 450, conductor 440, test terminal 231, test brush 230, contact233, right-hand high resistance winding of relay 246 to ground. Inparallel to this circuit, a circuit is also completed for relay 443.Relay 443, however, is not energized in series with the right-hand highresistance winding of relay 246. Relay 246 attracts its armature andcloses a circuit through its low resistance left-handwinding and thewinding of relay 236 to ground, in

parallel to the circuit through the righthand winding of relay 246. Thislow resist ance circuit reduces the potential on terminal 231suliiciently to render the selected trunk busy to other switches, andalso permit-s the rela- 443 to attract its armature.

Relay 443 y being energized, closes a circuit from ground over theleft-hand armature and back contact of relay 446, armature and frontcontact of relay 443, contact 453 of sequence switch 450, through thewinding of said sequence switch to battery and ground. Sequence switch450 moves out of position 1 and into position 3. In position 3 thefundamental circuit for controlling the operation of the final selectoris closed as follows: battery, through the winding of relay 452, contact471 (3), back contact and left-hand armature of relay 477, contact 444(3), conductor 414, middle terminal and brush of the second groupselector 216, contact 242, terminal 253, brush 254, contact 256, (9),conductor 296, cont-act 361, through the winding of stepping relay 355,armature and contact of relay 357-, conductor 297, contact 255 (9),brush 257, terminal 258, contact 244, upper brush and terminal of groupselector 216, conductor 413, contact 445, (3), conductor 612 to ground.Relay 452 is energized and completes a circuit from ground over itsarmature and front contact, contact 456 (3), winding of sequence switch450, to battery and ground, for moving sequence switch 450 out ofposition 3 and into position 4. In position 4, the trip spindle powermagnet 448 is energized in a circuit from battery through the winding ofsaid magnet, contact 447- (4), to ground at the front contact andarmature of relay 452. The trip spindle is rotated and for each positionpassed over, the interrupter contact 455 closes the following circuit toground, to shunt out the stepping relay 355 at the sender: battery,through the winding of relay 2, contact 449 (4), to ground atinterrupter contact 455. hen the register has returned to its normalposition the fundamental circuit is opened at the register sender andupon the next opening of the interrupter contact 455, relay 452 is deenergized. A circuit is thereupon closed from ground over the armatureand back contact of relay 452, contact 456 (4), winding of sequenceswitch 450, to battery and ground. Sequence switch 450 moves fromposition 4 into position 5.

The fundamental circuit is again closed preparatory to controlling theoperation of the selected set of brushes in the units selectionmovement. Relay 452, again being energized in the fundamental circuit,closes a circuit from ground over its armature and front contact,contact. 456 (5), winding of sequence switch 450, to battery and ground.Sequence switch 450 advances'from position 5 and into position 7. Inthis position the power magnet 461, which causes the operation of thebrush carriage, is energized in a circuit from battery through thewinding of said magnet, contact 451 (7), to ground at the front contactand armature of relay 452. For each set of terminals passed over by thebrushes 476, 479, and 470, the interrupter contact closes the followingcircuit, in shunt of the stepping relay 355: battery, through thewinding of relay 452, contact 449 (7), to ground at the interruptercontact 457. hen the unit's register has been restored to its normalposition the fundamental circuit is opened at the sender and upon thenext opening of the interrupter contact 457, the relay 452 is'deenergized. A circuit is then closed from ground over the armature andback contact of relay 452, con tact 456 (7) winding of sequence switch450, to battery and ground. Sequence. switch 450 moves from position '7into position 10. hen units selection has been completed the sequenceswitch controlling the register sender advances to a position where acir cuit is established for the energization of relay 339. This takesplace in the manner described in the aboveanentioned British Patent No.141,081, accepted April 15, 1920.

Relay 339, at. its right-hand armature, opens,

the circuit which up 'to this time has been holding the relay 222energized. Relay 222 releases its armature and closes a circuit fromground over its back contact, contact 238 (9) winding of sequence switch220, to battery and ground. Sequence switch 220 thereupon advances intoposition 11. Provided the tolloperator has released her dialing key 211by this time, the following circuit will be closed for relay 2221Battery,

through the winding of said relay, contact 237 (11), conductor 217, tipof jack 202,

. said'key is released and then advances into position 13 in the mannerjust explained. As sequence switch 220 leaves position 9, it opens atcontact 229, the above-traced circuit for relay 207 over conductor 218.This relay by releasing its armature closes a circuit for thesupervisory lamp 214. The illumination of lamp 214 indicates to theoperator Sequence that selection is completed and that the talkingconnection is established through to the called line. She now converseswith the subscriber at substation 420 and informs him that atoll call iswaiting to be extended to his line. The called subscriber closes hisconversation with the local subscriber, while the toll operatorwithdraws plug 201 from jack and reinserts it in the jack 200. Theoperator again builds up a connection over group selectors such as 210,215 and final selector 416 to the called line 420 and conversation withthe distant calling subscriber may take place.

The removal of plug 201 from jack 202 opens the circuit of relays 204and 235. Relay 204is deenergizedand causes the deenergization of relay206. Relay 235 by releasing its left-hand armature closes a circuit fromground, contact 223 (13), lefthand armature and back contact of relays35, contact 238 (13), winding of sequence switch 220 to battery andground. Sequence switch 220 advances from position 13 into position 17.In this position the brush carriage of the first group selector isrestored to its normal position. The circuit for energizing the brushcarriage power magnet 241 is traceable from battery through the windingof said magnet, contact 244 (17), back contact and armature of relayto'ground at contact 282. Upon the brush carriage reaching its homeposition, a circuit is completed from battery, over contact 243 (16 to18), brush 269, winding of relay 232 to ground. Relay 232 attracts itsarmature and opens the circuit of. the 'power magnet 241, causing thebrush carriage to cease to rotate. At the same time relay 232 closes acircuit from battery, through the winding of sequence switch 220,contact 226 (17), front contact'and armature of relay 232 to ground atcontact 282. Sequence switch 220 advances from )osition 17 intoposition 1. When the rushes 257 and 254 leave the terminals 258 and2530f the connecting circuit lead-' ing to the second groupselcctor, acondition is brought about in the well known manner for causing therelease of said selector. After the second group selector has beenreleased andthe test brush 230 has disengaged te'st terminal 231;, theholding circuit of relay 443 is broken permitting this relay to becomedeenergized. A circuit is then closed from ground over the lefthandarmature and back contact of relay 446,

armature and back contact of relay 443, contact 421 (2m 11), winding ofsequence switch 450 to battery and ground. Sequence switch 450 movesfrom position 10 over position 11, and into position '17. In thisposition the brush carriage of the final selector is restored to normalby means of a circuit from battery, through the winding of the brushcarriage power magnet 461, contact 451 (17), back contact and armatureof relay 452 to ground. In the normal posi tion of the brush carriage acircuit is completed from battery through the winding of relay 452,contact 449 to ground at the interrupter brush 457. Relay 452 attractsits armature to open the circuit of the power magnet 461, causing thebrush carriage to cease to rotate. Relay 452 also completes a circuitfrom ground over its armature and front contact, contact 456 (17),winding of sequence switch 450 to battery and ground. Sequence switch450 thereupon returns to its normal position 1. c

It will now be considered that the testing operator whose position isshown in Fig. 3, wishes to make a routine test of a group of subscriberslines. For this purpose the operators position is equipped with theusual testing apparatus diagrammatically indicated at 409." A connectingcircuit leading from the operators testing equipmentterminates in theplug 410. The operator by inserting the plug 410 in either of the jacks401 or 402, which are connected in n'rltiplewith the trunk 413', 414,appropriates for his use a final selector switch having access to thedesired group. of subscribers lines. In the particular type of switchused in this system, the terminal bank is arranged to accommodate 200lines. These lines are divided into two groups of 100 each, an evenhundred and an odd hundred. If the operator wishes to make tests in theeven hundred, he inserts the plug 410 in jacks 402 whereas if he desiresto test the line in theodd hundred group, the plug 410 is inserted injack 401.

Assuming that the plug 410 is inserted in jack-402, a circuit isthereupon completed from battery, over the sleeve of plug 410,

sleeve of jack 402, winding of relay 446 to ground. Relay 446 isenergized and closes a circuit from ground'overits left-hand armatureand front contact, contact 458 (1), left-hand winding of relay 477 tobattery and ground Relay 477 is energized and closes a holding circuit-tor itself as follows: battery through resistance 442, contact 441 (1),right-hand armature, front contact and right-hand winding of relay 477to ground. Relay 446 also closes a circuit from battery through thewinding of relay 452, contact 471 (1), right-hand armature and contactof relay 446, contact 478 (1), conductor 414, tip of jack 402, tip ofplug 410, left hand arm of switch 417 to ground at the operatorsequipment 409. Relay 452 is energized and a test is made to determinethe busy or idle condition of the register sender shown. in 5. Thissender is common to .a plurality of final selector switches such as theone'shown in Fig. 4. The circuit for making the test may be traced fromground over the armature and front contact of relay 452, contact 459(1), rigl'it-hand high resistance winding of relay 464, contact 467 (1),conductor 493, contact 622 .(1) of sequence switch 620, windings ofrelay 634 to battery and ground. It the sender is idle, full potentialwill be found on the conductor 493, and the high resistance winding ofrelay 464 receives sutficient current to become energized. Relay 464 byattracting its armature completes a low resistance path to groundthrough its left-handwinding, the winding of relay 462, and contact 466.This low resistance path being in shunt with the right-hand winding ofrelay 464, reduces the potential on conductor 493 to render the registersender busy.

When relay 462 is energized it closes a circuit from ground over itsarmature and contact, back contact and armature of relay 482, windingofrelay 431 to battery and ground, Relay 481, which is slow-to-operate,attracts its armature after an interval and completes through thewinding of sequence switch 450,

contact 453 (1), front contact and armature of relay 481 to ground atcontact 463 (1). Sequence switch 450 advances from position 1 intoposition 3. In positions 2 to 18 oi sequence switch 450 the followingcircuit is maintained for busy guard lamps 400 individual to trunk 413,414; battery through lamps 400 to ground at contact 463. hen sequenceswitch 450 reaches position 3, a circuit is closed from battery throughcoil 624, contact 639 (1), winding of stepping relay 625, contact 638(1), front contact and left-hand armature of relay 477, contact 444 (3),conductor 414, tip of jack 402, tip of plug 410 to ground at 409. Relay625 completes a circuit from ground over its armature and front contact,armature and back contact ofrelay 626, contact 636 (1), winding ofsequence switch 620 to battery and ground. position 1, into position 3.In position 3 of sequence switch 620, the interrupter is connected inseries with battery and the primary winding of dialing tone coil 624over contact 632. A dialing tone is thereby transmitted to the testingoperators equipment to inform him that the sender is ready to receiveimpulses.

The testing operator thereupon throws the switch 417 to include theimpulse sender 418 in series with the trunk 413, 414. The followingimpulse circuit is now completed for the transmission 01 impulses to thestepping relay 625: battery through the coil 624, contact 639 winding ofrelay 625. contact 638 (3), front contact and left hand armature ofrelay 477, contact 444 (3), con' ductor 414, tip of jack 402, tip ofplug 410, left-hand arm of switch 417, through the a circuit from.battery,

Sequence switch 620 moves from.

nkl.

switch 417, ring of plug 410, ring of jack" 402, conductor 413, contact445 (3), conductor 612 to ground. Relay 625 isenergized and closes acircuit from ground over its armature and front contact, arn'iature andfront contact of relay 6,26, contact 613 (3), right-hand winding,armature and contact of relay 629, contact 628 winding of the tensregister Z30, to battery and ground. It will be observed that the relay626 was energized when sequence switch 620 moved into position 3 in acircuit including contact 611, the armature and back contact of relay623. In parallel to the circuit above traced through the right-handwinding of relay 629, a circuit is also closed from ground and batterythrough impedance coil 631 and through the left-hand winding of saidrelay to ground at the armature and front contact of relay 625. Relay629 is made differential and does not attract its armature when bothwindings are simultaneously energized. The tens register 730 however isenergized and advances from position into position 1. The master contact731 of register 730 in closing between position 0 and position 1short-circuits the right-hand winding of differential relay 629,permitting this relay to attract its armature. The register 730continues to move into position 1 under the control of its mastercontact. operator manipulates {the impulse sender 418 to transmit thetens impulses, the step ping relay 625 releases its armature on eachinterruption of the impulse circuit. The circuit through the left-handwinding of differential relay 629 is opened at the first interruptionand this relay releases its armature. Upon the next closure of theimpulse circuit, the relay 625 is again energized and closes the abovetraced circuit for the register 7 and relay 629. V The register 730advances from position 1 into position 2, and relay 629 is againenergized over its left-hand winding. At the next interruption of theimpulse circuit relay 629 is again deenergized and this procedurecontinues, the register 730 being moved forward one step for eachimpulse contained in the tens series. The impulse sender 418 issoconstructed that the last interruption of the impulse circuit in eachseries is of a compa -atively longer duration than the precedinginterruptions. On this last interruption, the following circuits forrelay 634 is maintained closed for a sufiicient interval of time topermit said relay to attract its armature: battery through the windingsof relay 634, contact 622 (3), back contact and armature of relay 625 toground. Relay 634 be ing constructed to attract its armature slowly,does not operate on brief closures of its energizing circuit. Relay634when energized closes a circuit from battery through hen the theright-hand winding of relay 623 to ground at the armature and frontcontact of relay 634. Relay 623 closes a circuit from ground over itsarmature and front contact and left-hand Winding, contact 636 (3),winding ofsequence switch 620 to battery and ground. Sequence switch 620moves out of position 3. The circuit of relay 634 is then opened atcontact 622 and this relay by being energized permits the deenergizationof relay 623, so that sequence switch 620 upon reaching position 6 comesto rest in this position. The relay 634 has not been energized again inposition 6 of sequence switch 620 since the impulse circuit will havebeen closed by this time at the sender 418 to cause the energization ofrelay 625.

The relay 625 now closes a circuit from ground over its armature andfront contact, armature and front contact ofrelay 626, contacts 613 (6),right-hand winding and armature and contact of relay 629, contact 614(6), winding of the units register 740 to battery and ground. Inparallel to this circuit, the above described circuit for the left-handWinding of relay 629 is also closed. The register 740 becomes energizedand moves from position O into position 1. In passing from position 0into position 1, the master contact 745 short circuits therighthandwinding of relay 629 causing this relay to become energized. In responseto the first interruption of the impulse circuit during the transmission'of the units series, the relay 625 releases its armature and causes thedeenergization of relay 629. At the next closure of the impulse circuit,relay 625 becomes energized and the above traced circuit is closed forthe units register 740.

Register 740 inoves from position 1 into po-' sition 2. When the unitsseries has been completed, and the impulse circuit is opened for acomparatively long period on the last impulse, relay 634 attracts itsarmature and closes the above traced circuit for relay 623. Relay 623becomes energized and closes a circuit including contact'636 (6) fordriving sequence switch 620 out of position 6 and into position 9.

The register comprising the tensand units registers having beenpositioned in accordance with the designation of the particular line inthe even hundred subscribers lines that is desired to be tested, is nowoperated to control the tens and units selective movements of the finalswitch to establish a circuit from the testing operators position to theterminals of the desired line. As sequence switch 620 reaches position9, the fundamental circuit'is closed from battery through the winding ofrelay 452, contact 471 (3), right-hand armature and front contact ofrelay 446, contact 478 (3), contact 638 (9) winding of stepping relay625, contact 639 (9), contact and armature of relay 657 to ground.Relays 452 and 625 are energlzed in this circuit. Relay 452 closes acircuit from ground over its armature and front contact, contact 456winding'ofv brush tripping position is approached the n. al

interrupter 455 momentarily closes a circuit as follows in shunt of thestepping relay 625 in a fundamental circuit: battery through the windingof relay 452, contact 449 (4) to ground at interrupter 455. At the firstclosure of the interrupter contact 455, relay 625 is deenergized andcloses a circuit from ground over its armature and contact, contact 613(9), right-hand winding and armature and contact of relay 629, contact628 (9), contact 732 of register 730, winding of said register tobattery and ground. In parallel to this circuit, a circuit is alsoclosed for the left-hand winding of the differential relay 629. Theregister 730 is energized and moves forward one step from the positionto which it :as set by the operatoifs impulse sender 418. The mastercontact 761 in closing between positions short-circuits th right-handwinding of relay 629 permitting this relay to be energized and to openthe driving circuit of the register 730. Said register tl'iereforadvances through only one position where it awaits the deenergization ofrelay 629. As the brush tripping spindle reaches its tripping position,the interrupter contact- 455 opens and the stepping relay 6:15 isenergized. Relay 625 opens the circuit of the left-hand winding of relay629 permitting this latter relay to release its armature. As the brushtripping spindle approaches the next tripping position, the interruptercontact 455 closes, relay 625 is deenergized and the register 7 isdriven forward another position, in the manner described. This operationcontinues until register 7 30 reaches position 0. As soon thereafter, asrelay 625 is again deenergized, a circuit is closed from battery throughthe winding of sequence switch 620, contact 636 (9), contact 784 (0),contact 628 (9), contact and armatur and righthand winding of relay 629,contact 613 (9), back contact and armature of relay 625 to ground. Inparallel to thiscircuit, a circuit is also completed for relay 657.Relay 657 operates to open the fundamental circuit, while sequenceswitch 620 is energized and moves from position 9 into position 12. Thefundamental circuit having been opened at the armature and contact ofrelay 657, the relay 452 is deenergized as soon as the interruptercontact 455 is again opened, which indicates that the brush trippingspindle is in position to cause the tripping of the proper set ofbrushes. Relay 452 completes a circuit from ground over its armature andback contact, contact 456 (4), through the winding of sequence switch450 to battery and ground. Sequence switch 450 moves from position 4,into position 5.

The fundamental circuit is again closed to control the units selectivemovement of the final switch. Relay 452 by energizing closes a circuitfrom ground over its armature and front contact, contact 456 (5) thoughthe winding of sequence switch 450 to battery and ground for drivingsaid sequence switch out of position 5 and into position 7. In thisposition the brush carriage power magnet 461 is energized in a circuitfrom battery through the winding of said magnet, contact 451 7), frontcontact and armature of relay to ground. The brush carriage rotates theselected set of brushes 476, 479 and 470 over the level of terminalscontaining the terminals of the called line 420. The interrupter 457closes a circuit for relay 452 including contact 449 in shunt of thestepping relay 625 for each set of terminals passed over by the brushes.At the first closure of the interrupter contact 457, relay 625 isdeenergized and completes a circuit from ground over its armature andback contact, contact 616 (12), right-hand winding and armature andcontact of relay 629, contact 214 (12), contact 7 42 of the unitsregister 740, winding of said register to battery and ground. In themanner described in connection with the tens register 730,the unitsregister is driven from the position to which it was adjusted by theoperators impulse sender to position 0. Upon the next closure of theinterrupter contact 457, after the register 740 has reached its 0position, indicating that the brushes are about to make en gagement withthe terminals 483, 484 and 485 of the desired line, relay 625 isdeenergized. A circuit is now closed from battery through the winding ofsequence switch 620, contact 636 (12), contact 744 (0), back contact andarmature of relay 674, contact 743 (0), contact 614 (12), contact andarmature and right-hand winding of relay 629, contact 613 (12), backcontact and armature of relay 625 to ground. In parallel to thiscircuit, a circuit is also closed for relay 657. Relay 657 operates toopen the fundamental circuit while sequence switch 620 is energized andadvances from position 12 into position 14. As soon as the brushes 476,479 and 470 are accurately centered on the terminals of the desiredline, the interrupter contact 457 opens and relay 452 is deenergized. Acircuit is closed from ground over the armature and back contact ofrelay 452, contact 456 (7), winding of sequence switch 450 to batteryand ground. Sequence switch 450 moves into position 10. The sendersequence switch- 620 on reaching position 14' continues to move intoposition 16' by means of the following circuit: battery through thewinding of sequence switch 620, contact 636 (14), contact 734 (0),contact 628 (14), contact and armature and right-hand winding,

of relay 629,-contact 613 (14), back contact andarmature of .relay 625to ground. In position 16, the following circuit is closed to drivesequence switch 620 into its normal position 1: battery through thewinding of said sequence switch contact 636 (16), contact 744 (0), backcontact and armature of relay 674, contact 748 (0), contact 614 (16),contact, armature and right-hand winding of relay 629, contact 613'(16), back contact and armature of relay 625 to ground. The registersender is thus restored to its normal position and may be taken for useto control otherfi'nal selector switches.

If the test-ing operator wishes to" render the subscribers line 420busy, she depresses the key 405. This key closes a circuit overcontact-459 (10), right-hand winding of relay 464', contact 467 (10),brush 470, test terminal 485, Winding of cut-oft'relay 486 to batteryand ground. Relay 464 is energized and closes a low resistancepath overits left-hand winding, contact and left-hand armature, winding of relay462 to key 405 and ground. This low resistance path reduces thepotential on, the test terminal 485 to render it busy to other finalselector switches. Relay 462 closes a circuit from ground over itsarmature and contact, winch ing of rela 47 5 to battery and ground.Relay 475 shunts out the condensers 472 and 473" thus completing a fullmetallic'circuit from the operators testing equipment to the terminalsof the selected line.

it The operator by depressing the key 406, closes a. circuit for relay475 to complete a full metallic circuit to the selected line with;

out rendering said line busy. In this mah;

n'ei the line relay of the line 420 may be operated from the testingoperators position to initiate the operation of a line finder switchtoenable the performance of the necessary tests.

i 'It is frequently desired to test the seveial succeeding linesin thesame level in the switch. This may be accomplished withoutreleasing thefinal switch and resetting it onithe terminals of each individual line.After the first linehas been tested the operator depresses a key 408'and also a key 407. I The. closure of key 408 completes, a circuitfrombattery. over said key, left hand. winding of relay 411 to ground atthe backQcontact and armature of relay 412'. Belay 411 is energized andcompletes a circuit from ground through its right hand winding, theright-hand winding of relay 412, contact and armature'of relay 411, key407, contact 471 (10), winding of relay 452 to battery and ground.iRelays- 412 and 452' are energized in: this circuit.

The relay 412 locks up in: a circuit: frorni.

battery over the key 408, left-hand winding, front contactand armatureof relay lay 452 to ground: Thebrush carriagebe.

gin's to rotate. Asthe brushes approach, the next set of terminals inthe level, inter rupter contact 457 closes a" circuit-from'batterythrough the winding of relay 452, con-i tact 449 (11): to ground atinterrupter con? tact 457. This circuit shunts out therighte handWinding of relay 4'11 permittingthis, relay to be deeiiergized 'andz-toopen the: original energizing circuit of, relay "452.: When, therefore,the brushes center on the next set of line'terminals the interruptercontact 457 opens andfrelayrr452' issdeenergized. Relay 452 opensthe-circuit otthe brush carriage power magnet 46:1 and closes a circuitfrom battery throughfithe winding of the holding"magnet 46.5, coiltact454 (11), back contact and armaturef of relay 481, back contact andarmature/of relay 452 to ground. Magnet 465: operates to arrest themovement ofthe bruslncarriage'. In parallelto this circuit, a circuit isalso closed from battery through the winding of relay 482, contact 468(11) 'back contact and armature ofrelay'452 to ground. Relay 482 whichis slow-to-energi'ze at-- tracts its armature afteran interval andcloses a circuit for relay 481: to ground; at the back contact andarmature: of relay 452. Relay 481 which is also SlOVrtOPQll ergizeattracts its armature'after an interval and opens the circuit of theholding magnet 465. When the necessary tests have been performed on thesecond line of the level. .keys408 and 407 are again depressed causingthe energiz at'ion of relay 452, and

the consequent advance of the brush car'- with the relay 474. When relay474 is energized a circuit is completed as follows for relays 673 and674 in position 9 of the sender sequence switch 620: battery through thewindings of relays 674 and 673, contact 640 (9), armature and contact ofrelay 474 to ground at contact 466 (-l to 8-). Relays 674 and 673 lockup a circuit from battery through the windings of these relays, contactand armature of relay 673, contact 746 (1 to 9) of the units register740 to ground at contact 466. When the units register 740 reachesposition 9, in the units selection its does not move sequence switch 620out of position 12 and into position 14 as in the manner described inconnection with the selection of a line in the even hundred group.Instead, acircuit is closed as follows to drive register 740 out ofposition 0; battery through the winding of said register, front contactand armature of relay 674, contact 743 (0), contact 614 (12), contact,armature and right-hand winding of relay 6529, contact 613 (12), backcontact and armature of relay 625 to ground. The register 740 thereforeruns through an additional cycle causing the brush carriage of the finalselector to be driven over the first or even hundred section ofterminals and onto the terminals of the desired line in the second orodd hundred section. WVhen the register 740 passes from position 9 toposition 0, in its second rotation the locking circuit of relays 674ando673 is opened and these relays are deenergized. In position 0 of theregister 740 the above traced circuit is closed including contact 744and the back contact and armature of relay 674 for driving sequenceswitch 620 into position 14.

What is claimed is:

1. In a telephone system, a selective switch, a sender normallyconditioned to control the operation of said switch, a plurality ofautomatic switches, a second sender, means controlled by: said secondsender for operating said automatic switches to extend a connection tosaid selective switch, means controlled by said second sender foroperating said selective switch, to further extend said connection, aconnecting circuit, means for extending said circuit to said selectiveswitch, and means operative upon the extension of said connectingcircuit for rendering said first sender effective to control saidselective switch to further extend said connecting circuit.

2. In a telephone system, a selective switch,

a sender normally conditioned to control the operation of said switch, aplurality of automatic "switches, a second sender, means controlled bysaidsecond sender for operating said automatic switches to'extend aconnecthe selective switch to further extend the connecting circuit.

3.111 a telephone system, a selective switch, a sender normallyconditioned to,

control the operation of said switch, a plurality of automatic switches,a second sender, means controlled by said second sender for operatingsaid automatic switches to extend a connection to said selective switch,means controlled by said second sender for operating said selectiveswitch to further extend said connection, said first sender beininoperative during the control of the selective switch by said secondsender, a connecting circuit, means for extending said connectingcircuit to the selective switch, means responsive to the extension ofthe connecting circuit for placing said first sender in condition tocontrol the selective switch, means for setting said first sender, and

means for operating said selective switch in accordance with the settingof such sender to further extend said connecting circuit.

4. In a telephone system, a !selective switch, a sender normallyconditioned to control the operation of said switch, a plurality ofautomatic switches, a second sender, means controlled by said secondsender for operating said automatic switches to extend a connection tosaid selective switch, means controlled by said second sender for operating the selective switch to further extend said' connection, anoperators position, a connecting circuit thereat, means for extendingsaid connecting circuit to the selective switch, and means operativeupon the extension of said connecting circuit for rendering said firstsender effective to control the selective switch to further extend saidconnecting circuit.

5. In a telephone system, a selective switch, a sender normallyconditioned to control the operation of said switch, a plurality ofautomatic swtches, a second sender, means controlled by said secondsender for operat ing said automatic switches to extenda connection tosaid selective switch, means controlled by said second sender foroperating the selective switch to further extend said connection, anoperators position, a COD. necting circuit thereat, means for extendingsaid connecting circuit to said selective switch, means responsive tothe extension of the connecting circuit for placing said first sender incondition to control said selective switch, means. at the operatorsposition for setting said first sender, and means for opcrating saidselective switch in accordance with the setting of such sender tofurther extend said connecting circuit.

6. In a telephone system, a selective switch, a trunk leading to saidswitch, a sender normally conditioned to control the operation of saidswitch, means for extending a connection over said trunk to saidselective switch, a second sender, means controlled by said secondsender for operating said selective switch to further extend saidconnection, a connecting circuit, means for extending said connectingcircuit over said trunk to said selective switch, and means responsiveto the extension of said connecting circuit for rendering said firstsender efiective to control said selective switch to further extend saidconnecting circuit.

7. In a telephone system, a selective switch, a trunk leading to saidswitch, a sender normally conditioned to control the operation of saidswitch, means for extending a connection over said trunk to theselective switch, a second sender, means controlled by said secondsender for operating the selective switch to further extend saidconnection, said first sender being inoperative during the control ofsaid selective switch by said second sender, a connecting circuit, meansfor extending said connecting circuit over said trunk to the selectiveswitch, means responsive to the extension of the connecting circuit forplacing said first sender in condition to control said selective switch,means for setting said first sender, and means dependent upon thesetting of such sender for operating said selective switch to furtherextend said connecting circuit.

8. In a telephone system, a selective switch, a trunk leading to saidswitch, a sender normally conditioned to control the operation of saidswitch, means for extending a connection over said trunk to theselective switch, a second sender, means controlled by said secondsender for operating the selective switch to further extend saidconnection, said first sender being inoperative during the control ofsaid selective switch by said second sender, an operators position, aconnecting circuit thereat, manual means for extendlng said connectingcircuit over said trunk to said selective switch, means responsive tothe extension of said connecting circuit for placing said first senderin condition to control said selective switch, means at the operatorsposition for setting said first sender, and means dependent upon thesetting of such sender for operating the selective switch to furtherextend said connecting circuit.

9. In a telephone system, a selective switch, a sender normallyconditioned to control the operation of said switch, a plurality ofautomatic switches, a second sender, means controlled by said secondsender for operating said automatic switches to extend a connection tosaid selective switch, means controlled by said second sender foroperating said selective switch to further extend said connection, aconnecting circuit, means for extending said circuit to the selectiveswitch, and means operated upon the extension of said connecting circuitfor rendering said first sender effective to control said selectiveswitch to further extend said connecting circuit.

10. In a telephone system, a selective switch, a sender normallyconditioned to control the operation of said switch, a plurality ofautomatic switches, a second sender, means controlled by said secondsender for operating said automatic switches to extend a connection tosaid selective switch, means controlled by said second sender foroperating said selective switch to further extend said connection, saidfirst sender being inoperative during the control of the selectiveswitch by said second sender, a connecting circuit, means for extendingsaid circuit to the selective switch, and means responsive tov theextension of said connecting circuit for placing said first sender incondition to control the selective switch to further extend theconnecting circuit.

In witness whereof, I hereunto subscribe my name this 29th day ofNovember A. 1)., 1919.

LIPA POLINKOVVSKY.

